A regulator includes a differential circuit. The differential circuit compares an output voltage with a reference voltage to feed the comparison result back to an output transistor.
Accordingly, the output voltage becomes equal to the reference voltage.
In the background art, the differential circuit includes a pair of differential transistors to operate with constant current, a current source to drive differential transistors, and a current mirror circuit to balance driving currents of the differential transistors.
The regulator has a response speed depending on an operation speed of the differential circuit. The larger the driving current is, the higher the operation speed of the differential circuit is.
Accordingly, the differential circuit should operate with a large current all of the time in order to prevent a variation in the output voltage due to a sudden change in a load.
Unfortunately, the large current increases the power consumption of the regulator. In addition, an integrated circuit that includes a regulator and operates with low voltage can pose a drawback for the operation of the integrated circuit due to heat generation in the regulator by the increased power consumption.